Method and apparatus for creasing planar material

ABSTRACT

A method and apparatus for creasing planar material includes a pair of confronting drums between which the material is passed with at least one of the drums having at least one electrical filament thereon adapted to engage the planar material as it is passed between the drums for melting the planar material to a predetermined depth. The filaments are preferably quick heating and also dissipate heat quickly so that they can be activated and deactivated in short intervals so that the drums upon which the heat filaments are mounted do not heat up between the filaments.

CROSS-REFERENCE TO RELATED APPLICATION

This claims priority to Patent Cooperation Treaty Application No.PCTIUS00/21 811, filed Aug. 10, 2000, which application claims thebenefit of priority to U.S. provisional patent application Ser. No.60/148,834, filed Aug. 12, 1999. Each of the above-identifiedapplications is hereby incorporated by reference as though fullydisclosed herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to methods and apparatus forcreasing planar material and more particularly to a method and apparatusutilizing heated filaments to provide crease lines in planar materialsuch as fiberglass-type sheets.

2. Description of the Relevant Art

Planar materials which are semi-rigid in construction can many times befolded along a predetermined line by providing a crease in the materialalong the designated fold line. Such fold lines are desirable in ceilingpanels of the type described in copending provisional patent applicationSerial No. 60/148,834, filed Aug. 13, 1999 entitled “Ceiling System withReplaceable Panels,” priority to which is claimed herein. The disclosurein the aforenoted application is also hereby incorporated by reference.

Ceilings of building structures have taken numerous forms. They may beleft unfinished so that rafters or beams of the building structureitself are exposed or the rafter and beams may be covered as withdrywall, wood strips, plaster or other similar finishes. Walls ofbuilding structures may be similarly finished.

Another popular ceiling system is commonly referred to as a drop ceilingwhere a plurality of support bars are suspended from the unfinishedceiling so as to form a matrix having a plurality of side-by-sideopenings defined between the support bars. The openings are filled withpanels which are typically rigid acoustical panels, with the panelsbeing supported along their peripheral edge by the support bars.Although such drop ceilings have met with some success, there arenumerous disadvantages. One disadvantage is that there is very littlevariety in the aesthetics of the ceiling system since most acousticalpanels have the same general appearance, with another disadvantageresiding in the fact that the panels are rigid and brittle so that theyare easily breakable and, further, due to their rigidity, they aredifficult to insert into the opening provided therefore inasmuch as thesupport bars must partially protrude into the opening in order toprovide a support surface for the panels. Panels overcoming the aboveshortcoming are described in the aforenoted provisional application andit will therein be appreciated that the panels are formed from flexiblesheets of material, such as material having glass fibers embedded inresin, with some of the components of the panel being folded alongpredefined fold lines. It is difficult to fold such materials withoutfirst precreasing the material and accordingly an improved method andapparatus for providing creases in panels of this type would bedesirable.

It is to overcome the shortcomings in prior art systems and to provide anew and improved method and apparatus for creasing planar sheets ofmaterial that the present invention has been made.

SUMMARY OF THE INVENTION

The present invention pertains to a new and improved system forcauterizing planar sheets of material to form creases therein alongpredetermined lines. In some planar sheets, such as sheets made of glassfibers embedded in resins, it is desirable to crease the materialwithout damaging the glass fibers so that the material will remainresilient even after having been creased and folded along the creaseline.

In accordance with the present invention, a pair of confronting androtatable drums are mounted in slightly spaced relationship so that theplanar material to be cauterized and creased can be passed therebetween.At least one of the drums includes at least one conductive filament orwire so that the wire can be heated to a temperature exceeding thatwhich will cauterize the resin in a glass fiber panel.

In operation, the drums are rotated as the planar material is advancedtherebetween and as the drums are rotated, the heated filament orfilaments thereon engage the planar material at preselected locations tocauterize the material and thereby provide a crease in the materialconsistent with the size and configuration of the heated filament.

Other aspects, features, and details of the present invention can bemore completed understood by reference to the following detaileddescription of the preferred embodiment, taken in conjunction with thedrawings and from the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of an apparatus for creasing planar sheetsof material in accordance with the present invention.

FIG. 2 is vertical section of a portion of the apparatus shown in FIG.1, illustrating the confronting drums and the sheet of planar materialpassing there between.

FIG. 3 is a fragmentary isometric view of a panel formed with a sheetthat has been creased and folded with the apparatus shown in FIG. 1.

FIG. 4 is a side elevation of a planar sheet of material having beencreased with the apparatus of FIG. 1.

FIG. 5 is an end view of a folded sheet formed from a planar sheet ofmaterial that has been creased with the apparatus of the presentinvention and further showing a folding device for folding the creasedmaterial along the crease lines.

FIG. 6 is a fragmentary section taking along line 6—6 of FIG. 2.

FIG. 7 is a fragmentary section taking along line 7—7 of FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference to FIG. 1, an apparatus 10 in accordance with the presentinvention is illustrated. The apparatus includes a pair of confrontingcylindrical drums 12 and 14, a supply roll 16 of planar sheet material18 that passes around an idler roller 20 before being fed between theconfronting drums and into a folding apparatus 22 for folding the cutand creased planar sheets of material 18 into products, for example, ofthe configuration shown in FIG. 5. As will be appreciated with thedescription that follows, the apparatus 10 can be modified to formvarious types of creases 24 in planar sheet material in accordance withdesired fold lines 26 (FIG. 5) for forming products 27 of variousconfigurations. The product illustrated in FIG. 5 is merely exemplary ofa product that can be formed from a creased sheet of planar material,wherein the planar material has been cauterized to form the crease withthe apparatus of the present invention. The product shown in FIG. 5 canbe incorporated, for example, into a ceiling panel 29 as shown in FIG. 3of the type described in more detail in the aforenoted provisionalpatent application.

The planar material 18 to be creased in accordance with the presentinvention may be provided in rolls or in flat sheets or strips such thatthe material can be advanced between the pair of confronting drums 12and 14. The sheet or strips of material to be creased are precut to apredetermined width that can be accommodated by the length of therollers.

A material found to be particularly suitable for cauterizing in formingcrease lines with the method and apparatus of the present inventionincludes glass fibers imbedded in an acrylic resin with the fiberspreferably being relatively long and thin. The length of the glassfibers would preferably be in the range of one quarter inch to one inch.The thickness of the glass fibers would preferably be in the range ofseven microns to one-hundred microns, with fibers of ten to sixteenmicrons having proven to be particularly desirable. A material foundsuitable for this purpose is 100 GSM glass mat, number 8802 manufacturedby Johns Manville of Waterville, Ohio; or an alternative would bematerials from OJI Glasper in Japan and also Ahlstrom in Finland.

The drums 12 and 14 are disposed above and below the strips or sheets ofmaterial and mounted for rotation on axles 28. Both drums are formedfrom a metal cylinder 30 and have an outer electrically insulatingcovering 32. The covering or outer sleeve 32 may be made of siliconrubber which would preferably have a durometer rating of approximately80. In the disclosed embodiment, the drums have a plurality ofelectrically conductive wires 34, such as nickel chromium, extendingalong their length with the wires being connected to an electricalsource (not shown) so that they can be energized and de-energized in ashort period of time whereby the wires function as quick heat filaments,but upon deactivation lose the heat very rapidly. The insulating sleeveinsulates the metal drums from the nickel chromium wires so that thedrums do not heat up between the wires. As the strip or sheet material18 is passed between the drums, the nickel chromium wires 34 are engagedwith the material at preselected intervals corresponding to the distancearound the periphery of the cylindrical drum that the wires arepositioned. The wires, of course, come into engagement with the material18 along a line of alignment between the two cylindrical drums 12 and 14which is within an imaginary plane passing through the longitudinal axesof the drums. The nickel chromium wires are energized immediately beforeengagement with the strip material to cauterize the crease position onthe material and de-energized immediately thereafter for cooling thewires. In this manner, heat is applied to the material only along a lineof engagement with the wire and only for a short period of time, but itis enough heat to cauterize the crease position on the substrate of theglass fiber/resin material without damaging the glass fibers themselves.In other words, the heat penetrates and cauterizes the resin but willnot damage the glass fibers which have a higher melting point so thatthe structural integrity of the strip is left untouched. It will beappreciated that other composites could be used for the strip materialwith a preferred object being to utilize components with differentmelting temperatures so that one component is cauterized by the wireswhile another component is not.

It will be appreciated that if it were desired to crease only one sideof the material 18, one of the upper or lower drums 12 or 14 would notbe provided with the electrically conductive wires. It is also possiblethat ultrasonics or lasers could be used to crease the material again bycauterizing the resin base without damaging the glass fibers in thestrip material. The creases are provided at locations where the strip orsheet material is to be folded and these locations are spaced from eachother consistently with the spacing of the wires around thecircumference of the cylindrical drums.

It will be appreciated that the wires need not necessarily run along thelength of the drum on which they are mounted but could runperpendicularly thereto or even at an angle relative thereto dependingupon the location and orientation of the crease desired for the strip orsheet material. In some such cases the wires may be continuouslyenergized.

With reference to FIGS. 6 and 7, it will be seen that a plurality ofwires 34, which are each elongated loops, running along the length ofthe drums, are in engagement with non-conductive rings 36 havingconductive pads 37 at a location adjacent to the line of alignmentbetween the two drums. The rings are positioned at one end of the drums12 and 14 with the rings being in engagement with conductive brushes 38at each end of the looped wires. The conductive pads 37 on the rings arein turn connected to a source of electricity through an appropriateswitching system 38 which selectively controls the flow of electricityto the pads 37. The wires are thereby energized and de-energized inpulses as they are rotated by the line of alignment between the drumsand come into engagement with the planar material.

It will also be appreciated that the depth of the crease provided in thesheet or strip material 18 can be regulated by the diameter of the wire34 or the spacing of the drums 12 and 14. While it is preferable thatthe drums both be driven at a uniform speed but in opposite directions,i.e., clockwise and counterclockwise, it is possible that one of thedrums could be an idler while the other is driven or if there is enoughfrictional engagement between the sheet or strip material and the drums,the sheet or strip material could simply be drawn between the drums andboth drums could be idler drums which are forced to rotate uniformlythrough frictional engagement with the sheet or strip material which isbeing pulled therebetween.

Although the present invention has been described with a certain degreeof particularity, it is understood that the present disclosure has beenmade by way of example, and changes in detail or structure may be madewithout departing from the spirit of the invention as defined in theappended claims.

What is claimed is:
 1. An apparatus for creasing a planar material of apredetermined thickness comprising in combination: a means for creasinga planar material without completely penetrating through thepredetermined thickness of the planar material, and a means forconnecting the means for creasing without completely penetrating throughthe predetermined thickness of the planar material to a source ofelectricity.
 2. The apparatus of claim 1 further including means forselectively controlling the flow of electricity.
 3. The apparatus ofclaim 1 wherein said means for creasing without completely penetratingthrough the predetermined thickness of the planar material comprises apair of confronting drums having parallel axis of rotation andcylindrical surfaces, said cylindrical surfaces comprising anelectrically insulating material.
 4. The apparatus of claim 3 whereinsaid drums have a metal main body on which said insulating material isdisposed.
 5. The apparatus of claim 3 wherein at least one said drumscomprises at least one electrically conductive filament, said at leastone electrically conductive filament extends in parallel relationship tosaid axis of rotation of the drums.
 6. The apparatus of claim 1 whereinsaid cylindrical surfaces are an outer surface of said drums.
 7. Amethod of creasing without completely penetrating a planar materialcomprising the steps of: providing a pair of confronting cylindricaldrums having parallel axes of rotation with said drums defining apassage therebetween for said planar material to pass, wherein at leastone of said drums has at least one electrically conductive filament onits cylindrical surface, passing said planar material through saidpassage while said drums are counter-rotating so as to engage said atleast one filament with said planar material, providing an electricalcurrent to said at least one filament, and cauterizing withoutcompletely penetrating said material with said electrified filament toform a crease therein.
 8. The method of claim 7 wherein said electricalcurrent is provided to said at least one filament in predeterminedpulses.
 9. The method of claim 7 further including the step of providingsaid drums with a surface of an electrically insulating material. 10.The method of claim 7 wherein said material is a glass fiber materialimpregnated with resin and further including the step of melting theresin material during the cauterizing step without damaging the glassfibers.